100G Network Equipment Design and Test Methods

As 100G network topologies become increasingly common, network equipment vendors and designers at all levels of the supply chain are beginning to evaluate their verification and compliance testing methods. Many demonstrations at the OFC 2012 exhibition focused on 4-lane (4×25G/4×28G) implementation technology testing and electrical interface/physical layer testing of multiple key measurement parameters, including: BER performance correlated to eye diagrams; the amount of crosstalk that appears in jitter results.

What does this mean for test labs related to the high-speed network industry?

From an instrumentation perspective, the preferred test tool is an equivalent-time sampling oscilloscope because it provides far more than adequate bandwidth and exceptionally accurate eye diagram results for characterization. Many communications companies and network companies already own or are already renting equivalent-time sampling oscilloscopes, but updating the configuration to include 25+ Gb/sec clock recovery and jitter tools to identify crosstalk is very important for obtaining accurate test results in the 100G standard field.

In addition to an oscilloscope, it is best to use a BER tester suitable for 25+ G for many reasons: first, the BER tester can be used as a test pattern generator to help determine the stress points in the measurement setup (for example, stimulating crosstalk sources); second, it can also be used to evaluate the actual bit error rate calculation results.
As the IEEE802.3 standard evolves and the 100G test method is further standardized, we expect that further guidelines will appear in the test and measurement industry.